RF Front End Output Matching for Multi-Band Low-Loss Switching
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Solution Overview
Problem
Existing radio frequency front end modules cannot effectively handle different frequency bands and modes, leading to power loss, increased current consumption, and poor signal linearity due to the series connection of single-pole M-throw switches.
Innovation Solution
A multi-mode and multi-frequency radio frequency front end module is designed with an output matching unit comprising a first and second output matching module and switch modules, allowing for impedance matching and controlled signal routing to optimize signal transmission across various frequency bands and modes, reducing parasitic capacitance and power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-pole M-throw switch is used in series connection in the signal path for frequency band switching, then the device can support multiple frequency bands and modes, but additional power loss occurs, working current increases significantly, and heating is caused
Solution Approach 1:
The patent divides the output matching circuit into multiple independent parallel branches, each branch containing a switch and matching circuit components. This segmentation allows different frequency bands to be handled by different branches simultaneously or selectively, eliminating the need for series switching and reducing power loss associated with series switch connections.
Solution Approach 2:
The patent introduces parallel switching architecture as an intermediary structure between the power amplifier and the antenna. Instead of using a single series switch that causes power loss, the parallel switch network provides multiple independent paths, acting as an intermediary that routes signals with minimal power loss while still enabling frequency band switching functionality.
2Adaptability or versatility
If a single-pole M-throw switch is used in series connection, then frequency band switching is enabled, but parasitic capacitance between common port and output port affects signal matching effect
Solution Approach 1:
The patent segments the switching function into multiple independent parallel switches rather than using a single series switch. Each switch in the parallel configuration has its own independent terminals, eliminating the common port-to-output port parasitic capacitance path that exists in series switching configurations. This segmentation preserves signal matching accuracy across different frequency bands.
3Adaptability or versatility
If series connection of switches is used, then the device can select different frequency bands, but linearity and output power of radio frequency signal are significantly deteriorated
Solution Approach 1:
The patent implements a parallel switch network where each switch controls a separate matching branch for different frequency bands. This segmentation allows the radio frequency signal to pass through minimal switching elements in the active path, reducing the cumulative effect of switch non-linearities and preserving signal linearity and output power characteristics.
Solution Approach 2:
The parallel switch network acts as an intermediary that provides clean, low-loss signal paths for different frequency bands. By eliminating series switch connections, the intermediary structure prevents the introduction of non-linearities and signal degradation that would otherwise occur through multiple series switching stages.
Data Source
AI summary
Disclosed in the present invention are a multimode and multi-frequency radio frequency front end module, a chip, and a communication terminal. The radio frequency front end module comprises an input matching unit, an amplification unit, a first output matching module, a first switch module, a second matching module, and a control unit. The control unit is connected to the first switch module and is used for controlling a switch state of the first switch module, so as to input a radio frequency signal to one or more radio frequency transmission paths. According to the present invention, radio frequency transmission paths matching the radio frequency front end module can be selected according to different frequency bands under different modes and the control unit controls corresponding switches to be in switch-off and switch-on states, thereby implementing output of radio frequency signals at the different frequency bands under the different modes